Comorbidity (A complete guide)

Comorbidity refers to the presence of more than one medical condition in the same person.

What is comorbidity?

 In simple terms, comorbidity refers to the presence of more than one disorder in the same person.

For example, if a person is diagnosed with both social anxiety disorder (SAD) and major depressive disorder (MDD), they are said to have comorbid (meaning co-existing) anxiety and depressive disorders.

Other conditions that are seen to overlap include physical ailments such as diabetes, cardiovascular illness, cancer, infectious diseases and dementia.

Mental disorders that tend to show comorbidity also include eating disorders, anxiety disorders, and substance abuse.

 There are three different definitions of comorbidity, defined at different times in history.

The third one is the most recent, though not yet widely accepted:

·      a medical condition which exists simultaneously, but independently of, another condition in patients

·      two, or more than two, medical conditions existing simultaneously in a human body regardless of their interaction

·      indicates a medical situation in a patient that is caused by, and related to, other conditions in the same patient.

What is the history of comorbidity?

The term comorbidity was coined in 1970 by an American doctor and epidemiologist known as A.R. Feinstein.

He demonstrated comorbidity through the example of how people suffering from rheumatic fever also very often suffered from multiple other diseases.

A 2009, large cross-sectional national epidemiological study of comorbidity of mental disorders in primary care in Spain, published in the Journal of Affective Disorders, showed that among a sample of 7,936 adult patients, about half had more than one psychiatric disorder.

Moreover, according to a survey of national comorbidity in the US, 51% of patients who are suffering from major depression also have at least one other anxiety disorder, while 26% of them do not have any other type of mental disorder.

Pathways of comorbidity:

There are various different factors which determine the overall health of individuals, as well as the whole population, in every field of life.

These range from political context to biological characteristics. Therefore, they play an important role in finding out about a particular disease.

Diseases can be in different demographic groups, and different people can also get a variety of different diseases. 

Research has shown that there are three different ways in which many diseases can occur in same individual as follow:

·      chance

·      selection

·      bias.

  What are the causes of comorbidity?

There are many causes of non-random comorbidity, here are four:

·      when one disorder directly causes the second disorder, for example excessive use of alcohol, alcoholism, can lead to cirrhosis of the liver

·      the stress associated with the threat and lifestyle changes following on from receiving a diagnosis of heart problems, in other words, a previously existing disorder predisposes the patient to the onset of an anxiety disorder

·      common causes such as traumatic life events can predispose a patient to comorbidity anxiety and mood disorders

·      biological factors, where many common genetic factors play a part in bringing about the strong comorbidities which are found in mental disorder situations.

What are common comorbid conditions?

·      diabetes

·      cardiovascular illness

·      cancer

·      dementia

·      infectious diseases

·      substance abuse.

Why does comorbidity matter in neurodevelopmental disorders?

Neurodevelopmental disorders include development coordination disorder, hyperactivity disorder and learning disorders.

The potential cause for this comorbidity suggests they are neurobiological and genetic.

What are obesity comorbidities?

Obesity is a common contributor to various comorbidity situations.

Patients who are suffering from obesity often develop many additional medical conditions like insulin problems, hypertension, type two diabetes, stroke, gallbladder disease and even some types of cancers.

There are several important investigations taking place, in the medical world, around current obesity problems.

The important topics are the impact of adipose tissue inflammation and the proportional importance of subcutaneous vs. visceral fat in producing comorbidities.

For the development of every single comorbidity it is essential to identify the independent contribution of diet.

It is very important to clarify the impact of gender, duration of a given state and race.

Obesity and its comorbidities have several influencing factors and difficult interactions. 

 What are multiple comorbidities?

Multiple comorbidity is also referred to as multimorbidity and it greatly increases the complexity of managing disease in patients.

In developed countries, approximately one in four adults have at least two chronic conditions, and more than half of older adults have three or more chronic issues.

People are living longer with disability and multiple types of comorbidities, with important implications for global health care needs.

Sometimes, the term multimorbidity is used interchangeably with comorbidity, but essentially it indicates a condition or set of conditions that coexist in the content of a certain disease.

For example, an oncologist may be concerned with the effect of comorbidity on the management of lung cancer, whereas multimorbidity captures the general complexity of patients without focusing on any single disease.

In the US, different initiatives use this term as targeting the population of those who are improving their outcomes.

The national quality form defines multiple chronic conditions which have negative effects on a person and can decrease the functionalities of the human body as compared to the healthy body.

Here are the factors which are mainly affected by this:

·      decreased health status

·      low quality of life

·      improper functions

·      bad effect on decision making power or coordination.

Comorbidity greatly increases the complexity of managing disease in patients.

What Is the Difference between Complications and comorbidities?

A complication is a condition that arises during a hospital stay that often prolongs the length of stay.

Whereas comorbidity is a pre-existing condition that affects the treatment received across the entire length of the hospital stay.

How can comorbidity be diagnosed?

Approximately 90% of comorbidity sufferers are people living their lives in unfortunate conditions and particularly once or multiple times, they meet the criteria of disorder.

For example, there is a high rate of comorbidity between mental illness and drug disorders.

There is an argument for a comprehensive approach to intervention that identifies each disorder concurrently, providing   holistic treatment as needed.

Accordingly, patients entering treatment for psychiatric illnesses should also be screened for substance abuse disorders, and vice versa.

When people abuse drugs while under treatment, it may be necessary to observe, over a period of time, to distinguish between their previous and present condition and seek out the potential symptoms of comorbid mental disorders.

This practice would allow more accurate diagnosis and more effective treatment.

How can we prevent comorbidity?

All health care professionals play an important role in the prevention of this disease.

At a higher level, communication between mental health professionals and primary doctors is the main key to preventing people from entering into comorbid situations.

If a person has been diagnosed with mental or physical health conditions, medical staff should always keep the record of care which a person receives from different professionals, so that each can be aware of various other treatments.

For example, if SAD is left untreated for a long period of time, this can have a severe effect on a patient, and they could then develop depression which leads on towards anxiety depression.

If a person feels that they are suffering from mental disease, or having problems with their thoughts, they should contact a doctor immediately, otherwise it could result in severe negative effects.

Below is a graph of comorbidities which shows the relation between prevalence and diseases:

What is the conclusion of this investigation?

At the time of diagnosis (72% of females and 64% of males), comorbidities present in people living in the most deprived areas was  > 1 compared with the most affluent areas (67% of females and 59% of males).

Depression prevalence increased in all social strata but was more common in deprived areas.

Moderate clustering tendencies were observed, with concordant conditions grouped together and some variations between groups of different demographics. 

Depression was predicted to affect 33% of females and 15% of males diagnosed with type two diabetes in 2017.

In all sub-groups (by sex and deprivation), the proportion of people with zero comorbidities decreased during the follow-up period.

Comorbidities are common in this population, and high between-patient variability in comorbidity patterns emphasises the need for patient-centred healthcare.

Mental health is a growing concern, and there is a need for interventions that target both physical and mental health.

Side Note: I have tried and tested various products and services to help with my anxiety and depression. See my top recommendations here, as well as a full list of all products and services our team has tested for various mental health conditions and general wellness.

Frequently asked questions (FAQs) about comorbidity:

1.    What is comorbidity and why does it occur?

Comorbidity describes two or more disorders or illnesses occurring in the same person.

They can occur at the same time, or one after the other.

Comorbidity also implies interactions between the illnesses that can worsen the course of both.

2.    What are multiple comorbidities?

Multimorbidity, or multiple comorbidity, or multiple chronic conditions, is common and greatly increases the complexity of managing disease in patients.

3.    Is obesity a comorbidity?

Obese patients are at an increased risk of developing many medical problems, including insulin resistance and type 2 diabetes mellitus, hypertension, dyslipidemia, cardiovascular disease, stroke, sleep apnea, gallbladder disease, hyperuricemia, gout and osteoarthritis.

4.    Is diabetes a comorbidity?

Up to 75% of adults with diabetes also have hypertension.

Some other common comorbidities of diabetes are hyperlipidemia, cardiovascular disease, kidney disease, nonalcoholic fatty liver disease, obstructive sleep apnea and obesity.

5.    How does comorbidity affect recovery?

The presence of particular comorbid psychiatric disorders significantly lower the likelihood of recovery from anxiety disorders and increase the likelihood of their recurrence. 

6.    Why does comorbidity occur?

The reasons for comorbidity are complex. Furthermore, comorbidity is often associated with poor treatment outcome, severe illness course, and high service utilisation.

This presents a significant challenge with respect to the identification, prevention and management of people with comorbid disorders.

7.    What is a major comorbidity?

The presence of a major complication or comorbidity (MCC) or complication or comorbidity (CC) generally is representative of a patient that requires more resources; therefore, hospitals are paid more to care for these patients.

8.    Can obesity occur without comorbidity?

While it is not common, it is possible to suffer from obesity without having any known comorbidities.

Though comorbid conditions, such as diabetes, osteoporosis, sleep apnea and cardiovascular disease, might not be apparent at first, over time, they can become issues.

For more information try the following books:

Borderline Personality and Mood Disorders: Comorbidity and Controversy

In this insightful book a panel of distinguished experts reviews the last two decades of progress in scientific inquiry about the relationship between mood and personality disorders and the influence of this empirical data on our ways of conceptualizing and treating them.

This comprehensive title opens with an introduction defining general trends both influencing the expansion of the mood disorder spectrum and undermining clinical recognition and focus on personality disorders.

Nutritional Pathophysiology of Obesity and its Comorbidities: A Case-Study Approach

This book challenges students and practitioners to understand the role of nutrients within the pathophysiology and development of obesity, specifically those diseases which develop as a result of obesity.

Through a case-based approach, the author presents complex clinical scenarios that require multiple treatment strategies, including targeted diet modification as an adjuvant to medical therapy.

The book is divided into nine modules and five appendices, each of which covers aspects of obesity and its comorbidities.

References: December 2019

Arthritis and comorbidity: December 2018